7.3: Questions

Question 1 What is the primary source of energy that powers the hydrologic cycle?
From the Sun
From the Earth's core
From the atmosphere
From the oceans

Question 2 What process occurs when the rate of rainfall exceeds the ground's ability to absorb it?
Infiltration
Runoff
Transpiration
Evaporation

Question 3 What happens to the precipitation that falls into the ocean?
It makes its way back to the land
It is absorbed by plants
It completes its cycle and is ready to begin another
It evaporates immediately

Question 4 What is the process called when plants release water into the atmosphere?
Evaporation
Transpiration
Runoff
Infiltration

Question 5 How does water that infiltrates the ground eventually return to the atmosphere?
Through evaporation from the soil, lakes, and streams
Through runoff into lakes and streams
Through transpiration by plants
Through precipitation

Question 6 What is the term for the movement of water from the ground into plants and then into the atmosphere?
Transpiration
Evaporation
Infiltration
Respiration

Question 7 What is the primary mechanism by which the hydrologic cycle achieves balance?
The transport of water from the land to the ocean
The increase in the level of the world ocean
The decrease in global precipitation
The reduction in evapotranspiration

Question 8 What is the primary role of the precipitation that falls on land? and ?
It reduces evaporation from oceans
It gets stored in lakes
It makes the sea level lower
It contributes to sculpting Earth's surface

Question 9 How is the balance of the hydrologic cycle maintained?
All water eventually evaporates
The amount of evaporation is equal to the amount of precipitation
The amount of water circulating toward the poles is equal to the amount circulating toward the equator
The amount of water suspended as water vapor on air is equal to the amount of water resides in the ocean

Question 10 What is the primary factor that distinguishes a river from a stream?
Size of the channel and amount of water carried
Color of the water
Type of rocks in the channel
Speed of the current

Question 11 What is the term used to describe the area of land that drains water into a stream or river?
Drainage basin
Water table
Aquifer
Watershed area

Question 12 What is the purpose of a drainage divide in the context of streams and rivers?
To separate two drainage basins
To connect two rivers
To create a waterfall
To form a lake

Question 13 Which of the following is an example of a large-scale drainage divide?
Continental divide
River delta
Waterfall
Ocean current

Question 14 What percentage of the flow in the United States is carried by the Mississippi River?
40 percent
20 percent
60 percent
80 percent

Question 15 What is the primary location where most of the sediment carried by streams is derived?
Headwaters region
Trunk streams
River mouth
Coastal areas

Question 16 What happens to the speed of a river when it reaches the ocean or another large body of water?
It increases
It remains the same
It is varies in an unpredictable way
It is greatly reduced

Question 17 What is the term used to describe the main channels that transport sediment through a river system?
Tributary streams
Trunk streams
Delta streams
Coastal streams

Question 18 What type of sediments tend to be deposited upstream in a river system?
Fine sediments
Coarse sediments
Clay sediments
Silt sediments

Question 19 What is the process by which bedrock is broken down and transported downslope in the zone of sediment production?
Erosion and transportation
Weathering and mass movement
Deposition and reconfiguration
Sedimentation and ocean currents

Question 20 What is formed at the mouth of a river when it deposits most of its sediments?
A delta
A coastal feature
An ocean current
A trunk stream

Question 21 What is the balance maintained by trunk streams when they are in equilibrium?
The amount of sediment eroded equals the amount deposited
The amount of water flowing in equals the amount flowing out
The amount of sediment transported equals the amount produced
The amount of energy expended equals the amount gained

Question 22 What are the three main processes by which rivers move Earth's surface materials and sculpt landscapes?
Erosion, transportation, and deposition
Weathering, sedimentation, and reconfiguration
Mass movement, ocean currents, and coastal erosion
Sediment production, trunk streams, and delta formation

Question 23 What type of flow is characterized by water moving in nearly straight-line paths parallel to the stream channel in very slowly flowing streams?
Turbulent flow
Laminar flow
Gradient flow
Longitudinal flow

Question 24 What is the primary factor that contributes to a stream's ability to erode its channel?
Turbulence
Laminar flow
Stream discharge
Channel size

Question 25 How does the velocity of a stream affect its flow?
As velocity increases, the flow becomes more turbulent
As velocity increases, the flow becomes less turbulent
Velocity has no effect on stream flow
Velocity only affects stream flow in slow-moving streams

Question 26 What is the term used to describe the vertical drop of a stream over a specified distance?
Gradient
Discharge
Velocity
Longitudinal profile

Question 27 How does the gradient of a stream channel affect its flow velocity?
A steeper gradient results in greater velocity
A steeper gradient results in lesser velocity
Gradient has no effect on flow velocity
Gradient only affects flow velocity in slow-moving streams

Question 28 What is the measure most often used to compare the sizes of streams?
Discharge
Velocity
Gradient
Channel size

Question 29 What can be learned by examining a stream's longitudinal profile?
The cross-sectional view of a stream from its headwaters to its mouth
The volume of water flowing past a certain point
The vertical drop of a stream over a specified distance
The type of flow in a stream

Question 30 Why does discharge typically increase toward the mouth of a river in humid regions?
More tributaries contribute water to the main channel downstream
The channel size decreases downstream
The gradient of the stream decreases downstream
The velocity of the stream decreases downstream

Question 31 What happens to the channel size of a river as it flows downstream in humid regions?
It typically increases to accommodate the growing volume of water
It typically decreases as the volume of water decreases
It remains the same regardless of the volume of water
It only increases in slow-moving streams

Question 32 What is the point where a river empties into another water body called?
Mouth
Headwaters
Tributary
Delta

Question 33 What is the primary source of dissolved load in a stream?
Mineral matter from soil and bedrock
Surface runoff
Atmospheric deposition
Human activities

Question 34 Which type of load is carried by a stream when fine particles such as silt and clay are suspended in the water?
Suspended load
Bed load
Dissolved load
Dissolved sediment

Question 35 What is the process by which smaller particles, such as sand and gravel, move along the bottom of a stream channel?
Saltation
Suspension
Dissolution
Erosion

Question 36 How do larger particles, such as boulders, typically move along the bottom of a stream channel?
Rolling or sliding
Saltation
Suspension
Dissolution

Question 37 What happens to the bed load of a stream during periods of low water flow?
It is in motion intermittently
It is constantly in motion
It is always rolling
It is always suspended

Question 38 Which of the following types of load is not constantly in motion in a stream?
Evaporated load
Suspended load
Dissolved load
Bed load

Question 39 What is a characteristic feature of bedrock channels?
They are composed of loosely consolidated sediment
They have a high concentration of suspended load
They are formed in the lower reaches of river systems
They typically have steep slopes and transport coarse particles

Question 40 What type of streams tend to move in sweeping bends called meanders?
Streams that transport much of their load in suspension
Streams that transport large boulders
Streams with very steep slopes
Streams with very low discharge

Question 41 What is the term for the outside of a meander where active erosion occurs?
Cut bank
Point bar
Oxbow lake
Meander bend

Question 42 What happens to the coarser material that is eroded from the cut bank?
It is deposited as point bars on the insides of bends
It is carried away by the stream and never deposited
It is stored in the stream's channel
It is thrown back onto the cut bank

Question 43 What is the term for the new, shorter channel segment that is formed when a river erodes through the narrow neck of land between meanders?
Cutoff
Meander
Oxbow lake
Point bar

Question 44 What is the term for the abandoned bend that is formed when a river erodes through the narrow neck of land between meanders?
Oxbow lake
Cutoff
Meander
Point bar

Question 45 What is a characteristic of streams that flow in meanders?
They have relatively deep, smooth channels and transport mainly mud
They have very steep slopes and transport large boulders
They have very low discharge and transport little sediment
They have very wide channels and transport a lot of sand

Question 46 What is the primary type of sediment transported by streams that move in meanders?
Silt and clay
Sand
Gravel
Boulders

Question 47 What happens to the neck of land between meanders over time?
It is gradually narrowed
It is gradually widened
It remains the same
It is completely eroded away immediately

Question 48 What is an example of a river that transports much of its load in suspension and flows in meanders?
The Lower Mississippi River
The Colorado River
The Nile River
The Amazon River

Question 49 What is the primary process that occurs when a stream's gradient is steep and the channel is well above base level?
Lateral erosion
Downcutting
Mass movement
Weathering

Question 50 What is the typical shape of a valley formed by a stream with a steep gradient and a channel well above base level?
V-shaped
U-shaped
Flat
Oval

Question 51 What features are commonly found in a V-shaped valley?
Rapids and waterfalls
Floodplains and meanders
Deltas and estuaries
Glaciers and canyons

Question 52 What is the result of a stream's meandering pattern and lateral erosion?
A widening of the valley and formation of a floodplain
A deepening of the streambed and formation of a canyon
A decrease in the stream's energy
An increase in the stream's gradient

Question 53 What is the term for the broad, flat valley floor covered with alluvium that forms as a result of lateral erosion?
Floodplain
Delta
Canyon
Waterfall

Question 54 What happens to the floodplain when a river overflows its banks during flood stage?
It remains unaffected
It is eroded away
It is inundated with water
It becomes a delta

Question 55 What happens to a stream's forward motion when it enters the relatively still waters of an ocean, a lake, or an inland sea?
It speeds up
It remains constant
It slows down
It becomes turbulent

Question 56 What is the result of the stream's gradient continually lessening as a delta grows outward?
The channel becomes choked with sediment
The channel becomes deeper
The channel becomes narrower
The channel becomes straighter

Question 57 What is the term for the smaller channels that a main channel divides into as a delta forms?
Distributaries
Tributaries
Meanders
Levees

Question 58 How are natural levees built in meandering rivers that occupy valleys with broad floodplains?
By years of successive floods depositing coarser sediment adjacent to the channel
By years of erosion cutting into the valley floor
By human construction to control flooding
By tectonic activity uplifting the valley floor

Question 59 What happens to the flow velocity of water when a stream overflows onto the floodplain?
It increases significantly
It remains constant
It drops significantly
It becomes turbulent

Question 60 What is the primary source of almost all groundwater?
Runoff from the land surface
Evaporation from the oceans
Transpiration from plants
Rainfall that soaks into the ground

Question 61 What is the term for the near-surface zone where water is held by molecular attraction as a surface film on soil particles?
Belt of soil moisture
Zone of saturation
Water table
Unsaturated zone

Question 62 What is the name of the upper limit of the zone where all open spaces in sediment and rock are completely filled with water?
Water table
Belt of soil moisture
Zone of saturation
Unsaturated zone

Question 63 Why can't water in the unsaturated zone be pumped by wells?
It clings too tightly to rock and soil particles
It is too deep underground
It is too salty
It is too cold

Question 64 What determines the quantity of groundwater that can be stored in a material?
Porosity of the material
Permeability of the material
Density of the material
Temperature of the material

Question 65 What is the term for the percentage of the total volume of rock or sediment that consists of pore spaces?
Porosity
Permeability
Density
Viscosity

Question 66 What is the ability of a material to transmit a fluid called?
Permeability
Porosity
Density
Viscosity

Question 67 How does groundwater move through the ground?
By twisting and turning through interconnected small openings
By flowing through large underground channels
By being pumped by well
By evaporating into the air

Question 68 What type of layer can hinder or prevent water movement?
Impermeable layer
Permeable layer
Porous layer
Saturated layer

Question 69 What is the area above the water table where the soil, sediment, and rock are not saturated called?
Unsaturated zone
Saturated zone
Belt of soil moisture
Zone of saturation

Question 70 Which type of rock is likely to allow contaminated groundwater to travel long distances without being cleansed?
Permeable sandstone
Highly fractured crystalline limestone
Impermeable clay
Non-porous granite

Question 71 What is the main reason why water in extremely permeable aquifers may not be purified?
It flows too slowly through the aquifer
It is not in contact with the surrounding material long enough
It is too cold
It is too salty

Question 72 How does the weight of the overburden affect the sediment when water is withdrawn from an aquifer?
It is transferred to the sediment, causing it to subside
It is lifted off the sediment, causing it to rise
It remains unchanged
It is distributed evenly throughout the aquifer

Question 73 Which of the following types of aquifers can sometimes purify water after it has traveled only a few dozen meters through it?
Those consisting of sand or permeable sandstone
Those consisting of highly fractured crystalline rock
Those consisting of non-porous granite
Those consisting of impermeable clay

Question 74 What is the result of the increased pressure on the sediment grains as the water pressure drops due to withdrawal of water from an aquifer?
The ground subsides
The ground rises
The sediment grains become less dense
The aquifer becomes more permeable

Question 75 What is unique about the solubility of limestone in water?
It is easily dissolved by pure water
It is insoluble in water containing carbonic acid
It is nearly insoluble in pure water but easily dissolved by water containing carbonic acid
It is equally soluble in all types of water